1. Field of the Invention
The present invention relates to a biopsy device for removing a tissue sample from a mass to be examined through a biopsy needle, which is inserted into the mass to be examined.
2. Description of the Related Art
Biopsy devices have been developed for removing a tissue sample from a suspicious region of a subject, and for examining the tissue sample in order to perform a disease diagnosis on a patient.
Japanese Laid-Open Patent Publication No. 10-201749 discloses a system, which includes a mammographic apparatus for acquiring radiographic images of the breast region of a patient to be examined, together with a biopsy device that is incorporated into the mammographic apparatus. According to the disclosed system, the breast is positioned between an image capturing base and a compression plate, and then the breast is imaged from two directions in order to produce stereographic image information. Based on the stereographic image information, the positional information of a region to be biopsied is obtained. Then, the biopsy device, which is incorporated into the mammographic apparatus, is operated so as to insert a biopsy needle into the region to be biopsied according to the acquired positional information, whereby a tissue from the region to be biopsied is sampled.
Japanese Laid-Open Patent Publication No. 10-165403 discloses a biopsy device in detail. As shown in FIG. 7 of the accompanying drawings, the biopsy device includes a compression plate 4, which compresses and positions the breast 6 against a support base 2, and a biopsy needle 10, which is inserted into the breast 6 that has been positioned through an opening 8 defined in the compression plate 4. A tissue sample then is removed from the breast 6 through the biopsy needle 10. The biopsy needle 10 is held by a robot arm assembly 12, which is movably mounted on the compression plate 4. The robot arm assembly 12 includes a first arm 16 having an end pivotally supported on a post 14 fixed to the compression plate 4, and which is angularly movable about the post 14 in the directions indicated by the arrows parallel to the compression plate 4, and a second arm 18 having an end pivotally supported on the other end of the first arm 16, and which is angularly movable about the other end of the first arm 16 in the directions indicated by the arrows parallel to the compression plate 4. The biopsy needle 10 is mounted on the other end of the second arm 18 for movement in the directions indicated by the arrows, which are perpendicular to the compression plate 4. Based on the positional information of the desired region of the breast 6 to be biopsied, which has been acquired by a modality such as an MRI system or the like, the robot arm assembly 12 is controlled in motion so as to bring the biopsy needle 10 toward the region to be biopsied in order to remove a tissue sample therefrom.
If the robot arm assembly 12 is moved accidentally while the biopsy needle 10 resides within the breast 6, then the breast tissue may possibly become damaged by the biopsy needle 10. The robot arm assembly 12 could accidentally be moved when a technician operates the biopsy device by mistake, or if the robot arm assembly 12 moves in error.